title: Positive supercoiling of mitotic DNA drives decatenation by topoisomerase II in eukaryotes.
abstract: DNA topoisomerase II completely removes DNA intertwining, or catenation, between sister chromatids before they are segregated during cell division. How this occurs throughout the genome is poorly understood. We demonstrate that in yeast, centromeric plasmids undergo a dramatic change in their topology as the cells pass through mitosis. This change is characterized by positive supercoiling of the DNA and requires mitotic spindles and the condensin factor Smc2. When mitotic positive supercoiling occurs on decatenated DNA, it is rapidly relaxed by topoisomerase II. However, when positive supercoiling takes place in catenated plasmid, topoisomerase II activity is directed toward decatenation of the molecules before relaxation. Thus, a topological change on DNA drives topoisomerase II to decatenate molecules during mitosis, potentially driving the full decatenation of the genome.
authors.affiliation: Medical Research Council (MRC) Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, London, UK. Jon.Baxter@sussex.ac.uk
authors.forename: J
authors.initials: J
authors.lastname: Baxter
authors.forename: N
authors.initials: N
authors.lastname: Sen
authors.forename: V López
authors.initials: VL
authors.lastname: Martínez
authors.forename: M E Monturus
authors.initials: ME
authors.lastname: De Carandini
authors.forename: J B
authors.initials: JB
authors.lastname: Schvartzman
authors.forename: J F X
authors.initials: JF
authors.lastname: Diffley
authors.forename: L
authors.initials: L
authors.lastname: Aragón
mesh_terms: D002453:Cell Cycle; D020090:Chromosome Segregation; D004261:DNA Replication; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D043864:DNA, Catenated / Q000737:chemistry* / Q000378:metabolism; D004271:DNA, Fungal / Q000737:chemistry* / Q000378:metabolism; D004278:DNA, Superhelical / Q000737:chemistry* / Q000378:metabolism; D019281:Dimerization; D008938:Mitosis; D009690:Nucleic Acid Conformation; D010957:Plasmids; D012441:Saccharomyces cerevisiae; D008941:Spindle Apparatus / Q000378:metabolism
chemical_list: D043864:DNA, Catenated; D004271:DNA, Fungal; D004278:DNA, Superhelical; D004250:DNA Topoisomerases, Type II